Method and apparatus for producing a tobacco rod

ABSTRACT

METHOD AND APPARATUS FOR MANUFACTURING CIGARETTE RODS WHEREIN A STREAM OF SHREDDED TOBACCO IS MOVED FROM A PNEUMATICALLY ASSISTED SUPPLY INTO A GROOVE PROVIDED AT THE PERIPHERY OF A SUCTION WHEEL, THE VELOCITY AND DIRECTION OF MOVEMENT OF THE STREAM OF TOBACCO FIBERS BEING REGULATED SO AS TO CAUSE THE SAME TO IMPINGE THE GROOVE SO THAT THE BUILDING PLANE FORMED AT THE POINT OF INTERSECTION OF THE TOBACCO STREAM AND THE END OF THE TOBACCO ROD BEING FORMED, HAS A PREDETERMINED INCLINATION, TANGENT TO THE INNERMOST PART OF THE GROOVE LOCATED AT THE PERIPHERY OF THE WHEEL, AT THE POINT WHERE THE PLANE INTERSECTS THIS GROOVE FORMING A PREDETERMINED ACUTE ANGLE OR, WHEREBY THE FIBERS BECOME LAYERED TO FORM A UNIFORMLY DENSE AND HOMOGENEOUS TOBACCO ROD STRUCTURE WITH THE FIBERS THEREOF ASSUMING PRIMARILY A POSITION LOCATED AT THE ACUTE ANGLE A WITH RESPECT TO THE AXIS OF THE TOBACCO ROD.

United States Patent (72] Inventors Friedrich Wllde;

Johannes llerrmann, Dresden, Germany [21] AppLNo. 668,859 [22] Filed Sept.l9,l967 [45] Patented June28, 1971 [73] Assignee VEB Tabalr-Und lndustrlemaschlnen Dresden DresdemGerrnany [54] METHOD AND APPARATUS FOR PRODUCING A TOBACCOROD 6C1a1ms,51)rawh1gFigs.

[52] U.S.Cl. 131/84, 131/110 [51] lntJ A24c5/18 [50] FieldotSeareh 131/8, 14, 21 (D), 84 {8),84 (C), 1 l0, 1 10 (AA), 110 (A) [56] References Cited UNITED STATES PATENTS 1,911,711 5/1933 Norris..... 131/14 1,999,120 4/1935 Werner.. (l31/84BUX) 3,030,965 4/1962 Labbe 131/110X 3,039,473 6/1962 Schubert.... l3l/84(C) 3,059,650 10/1962 Gamberini..... l31/84(B)X 3,074,413 1/1963 McArthur 131/846) V as" it 2 3,170,467 2/1965 DiGiacomqetal 131/11ox 3,262,457 7/1966 Gamberini 131/11ox 3,313,665 4/1967 Berger 131/a411ux FOREIGN PATENTS 1,479,302 3/1967 France 131/2103) 900,182 12/1953 Germany 131/84 359,080 1/19 2 Switzerland Primary Examiner-Joseph S. Reich Attorney-Nolte and Nolte ABSTRACT: Method and apparatus for manufacturing cigarette rods wherein a stream of shredded tobacco is moved from a pneumatically assisted supply into a groove provided at the periphery of a suction wheel, the velocity and direction of movement of the stream of tobacco fibers being regulated so as to cause the same to impinge the groove so that the building plane formed at the point of intersection of the tobacco 24 I3 36 I I2- 22 PATENTED'JUN28IQ7I SHEET 1 0F 2 JOHANNES HERRMANN PATENTED JUN28 I971 SHEET 2 BF 2 FIG. 4

FIG. 3

FIG. 5

INVENTORS FRIEDRICH WILDE JOHANNES HERRMANN METHOD AND APPARATUS FOR PRODUCING A TOBACCO ROD BACKGROUND OF THE INVENTION The present invention relates to the treatment of fibers such as tobacco fibers derived from shredded tobacco.

In particular, the invention relates to a method and apparatus for continuously manufacturing a rod of pourable fibers of this type.

With the method and apparatus of the invention the fibers are pneumatically supplied to a given outlet opening of a pneumatic supply means which is spaced from the grooved periphery of a rotary suction wheel at whose grooved periphery the rod is continuously formed, and at the outlet opening of the pneumatic supply means the stream of tobacco has a high speed for separation of the tobacco fibers from each other, while at the same time the stream has a low density and a small cross section so as to be directed in this way along a predetermined path to the grooved periphery of the rotary suction wheel.

In the manufacture of cigarettes it is known to provide continuous rods of tobacco of the above type, and as the machines which make these rods have their outputs increased there is to an increasing extent the problem of achieving a homogeneous continuous tobacco rod of sufficiently great transverse elasticity as well as tightness or density of the cigarette filling while at the same time utilizing the smallest amount of tobacco for this purpose.

A relatively large number of mechanical and pneumatic methods and apparatus are known for manufacturing continuous tobacco rods, and all of these known methods and apparatus are designed to attempt to achieve a high rod speed while at the same time maintaining as much as possible a homogeneous and uniform fiber structure as well as a good transverse elasticity and thus a good filling capability for the rod of tobacco. The best results have been achieved up to the present time with that type of method and apparatus where the tobacco rod is pneumatically formed. With one type of a method and apparatus the rod is formed at the grooved periphery of a suction wheel which is provided at the innermost part of the groove at its periphery with suction openings through which air flows into the interior of the wheel so as to form the rod in the periphery of this rotary suction wheel. The shredded tobacco is delivered either mechanically or pneumatically to the grooved periphery of the suction wheel, and a more or less satisfactory separation of the fibers from each other takes place also either mechanically or pneumatically.

There are known devices where the shredded tobacco is delivered from a suitable distributing device onto a supply conveyor having a conveyor belt on which the fibers are spread and from which the fibers are formed into an elongated unit at high speed while consuming a relatively small amount of tobacco, this material being delivered into the groove at the periphery of the suction wheel where the rod is formed at a speed determined by the speed of rotation of the wheel. With this type of construction the point from which the tobacco is delivered to the suction wheel, namely the delivery end of the conveyor belt, is spaced from the periphery of the suction wheel.

In one type of construction of this type, because of the high speed with which the shredded tobacco leaves the delivery end of the conveyor belt, the tobacco is forcefully thrown into the groove at the periphery of the suction wheel. A modified construction of this type utilizes a stream of compressed air which is directed against the grooved periphery of the'suction wheel in order to maintain the impulse for moving the tobacco between the delivery end of the conveyor belt and the suction wheel. The shredded tobacco can be delivered to the suction wheel in an amount which is in excess of the amount actually required, and the excess tobacco is separated by way of a suitable blade which forms a cover for the grooved periphery of the suction wheel.

In additional devices of this type there are beater rollers which receive the tobacco from the delivery end of the conveyor belt and deliver it into the groove at the periphery of the suction wheel, and with this construction the intermediate space between the conveyor belt and the suction wheel is bridged by guide baffles made of sheet metal.

Also, there are known structures of this type which will distribute the shredded tobacco from the delivery end of the conveyor belt into the groove at the periphery of the suction wheel over a relatively large sector thereof.

With all of these known methods and apparatus it is assumed that, at the free space extending between the delivery end of the conveyor belt and the grooved periphery ofthe suction wheel, the shredded tobacco, which is centrifugally delivered to the grooved periphery of the suction wheel, no longer has the particles thereof united to each other so that in this way there will be a uniform formation of the rod of tobacco. However, experience has shown that with the known mechanical methods for separating the tobacco fibers, an adequate and satisfactory separation thereof from each other is not capable of being achieved so that the uniform density of the tobacco structure in the finished rod can only be achieved with these known methods and apparatus to a limited extent. Furthermore, with these known structures it is not possible, taking into consideration the different qualities of the tobacco, to form the rod of tobacco at a precisely determined optimum location in the groove of the periphery of the suction wheel, in order to be able to achieve in the fiber structure of the finished rod the desired directions in which the fibers extend, as well as the desired homogeneity, density of the fiber structure, and transverse elasticity of the rod. The use of beater rollers for centrifugally depositing the tobacco fibers into the groove at the periphery of the suction wheel also results in an additional shortening of the tobacco fibers which is undesirable.

ln order to avoid these drawbacks, it has been proposed to carry out the separation of the fibers from each other in a pneumatic manner so that in this way it might be. possible to improve the structure of the rod while at the same time increasing the output of the machine which forms the cigarette in rod form.

In a known structure of this latter type the shredded tobacco is delivered with impact from a roller type of distributor by means of beater rollers into a passage which accommodates a stream of tobacco, and this stream is delivered by suitable rollers into the air stream of a suction wheel in which the air flows transversely with respect to its axis so that the fibers are deposited at the periphery of the wheel over a relatively large sector along which the fibers are distributed.

With this type of construction there is indeed a good loosening of the fibers from each other, but the relatively long building length of the pneumatically supplied shower of tobacco fibers over the periphery of the suction wheel results in the building of the rod along a relatively fiat building angle of small inclination. The particles of tobacco are thus directed primarily longitudinally of the rod parallel to the axis thereof, so that the fibers become layered in a direction which is parallel to the rod axis. As a result the transverse elasticity in the rod, and thus its capability of filling the interior of the cigarette, is sharply reduced.

lt has also been proposed to deliver the shredded tobacco from a roller type of distributor by means of beater rollers into the suction inlet of a supply conduit which is under the influence of a suction stream and in which the shredded tobacco is loosened into its individual fibers while being preliminarily compacted in an intertia type of compactor whereupon the stream of compacted fibers is taken up by a stream of compressed air and delivered by a metering device to the passage of a rotary wheel in such a way that the stream of tobacco reaches the latter wheel tangentially. ln this way the tobacco becomes packed within the wheel passage, which is closed by a suitable band over a predetermined sector of the wheel, and because of the varying degree of compression of the particles during the packing thereof this variation in the compacting pressure of the particles is used to control the metering device.

Experience has shown, however, that as a result of the tangential delivery of the individual loosened fibers of shredded tobacco into the passage of a wheel of this type and the subsequent packing of the particles to provide the tobacco rod by way of a compacting which takes place along the axis of the rod, a uniform layering of the tobacco fibers and thus a uniform density of the rod cannot be achieved, although the preliminary conditions for a good release of the fibers and separation thereof from each other are created. The layering of the fibers takes place primarily in a direction which extends perpendicularly across the axis of the rod.

SUMMARY OF THE INVENTION It is thus a primary object of the present invention to provide a method and apparatus which will avoid the above drawbacks.

Thus, it is an object of the invention to provide a layering of fiber particles, particularly particles of shredded tobacco, with the particles separated from each other to a sufficient extent in dependence upon the quality of the tobacco, so as to provide therefrom a rod of tobacco which has a uniform layering of the fibers, a high degree of homogeneity, a uniform density of the fiber structure, and a good transverse elasticity for the resulting rod.

In particular, it is an object of the invention to achieve this type of tobacco rod structure while utilizing pneumatic apparatus for supplying and preliminarily compacting a stream of fiber particles.

Also, it is an object of the invention to provide a method and apparatus by means of which the stream of tobacco is acted upon in such a way that the tobacco particles become layered in the groove of a suction wheel in which the rod is continuously formed at a predetermined circumferential region of the peripheral groove, with the possibility of selecting the location where the rod initially builds in the groove.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a horizontal schematic section illustration of an apparatus according to the invention, shown partly in section;

FIG. 2 is a fragmentary enlarged sectional view taken along the line 2-2 in FIG. 1, in the direction of the arrows;

FIG. 3 is a fragmentary sectional view ofa rod produced by the apparatus shown in FIG. 2;

FIG. 4 is a view similar to FIG. 2, showing a modified means for controlling the direction of a portion of an air and tobacco stream therein; and

FIG. 5 is a view similar to FIG. 3, of a portion of a rod produced by the apparatus shown in FIG. 4.

DESCRIPTION OF PREFERRED EMBODIMENTS As may be seen from FIG. 1, the apparatus of the invention which is used to perform the method of the invention includes a distributing unit made up ofa pair of driven rollers 1 having sharp pins projecting outwardly from the periphery thereof, and only one of these rollers 1, which receive the shredded tobacco, driven rollers is illustrated. These deliver a carpet of tobacco to a picker wheel 2 which has attached to its periphery attached to its pins projecting therefrom and which rotates at a higher speed than the rollers 1.

A pneumatic supply means has its inlet end located adjacent to the picker wheel 2. This pneumatic supply means includes the inlet end of the convergent duct 3 which communicates with the inlet ofconduit 4 which in turn delivers the fibers to a dust separating device comprising a conical tube of louvered metal 5 having a series of frustoconical sheet metal rings 6 partly nested one into the next, and a casing 7 which concentrically surrounds the separating device 5. This casing 7 communicates at its left end, as viewed in FIG, 1, with the inlet ofa radial fan 9 of high output while forming at its end distant from the fan, with the last of the series of the rings 6, the outlet opening 8 of the pneumatic supply means. This outlet opening 8 is of a small cross section, on the order of 20-30 times smaller than the cross-sectional area of the inlet end of the convergent duct 3.

As is indicated in FIGS. 2 and 4, the outlet opening 8 of the pneumatic supply means is situated at a given distance from a suction wheel 21 which rotates clockwise about a horizontal axis, and the tobacco stream is delivered from the outlet open ing 8 into a completely surrounded and enclosed chamber 12 which extends between the outlet opening 8 and the suction wheel 21. This enclosure chamber includes sidewalls 13 and 14, an upper limiting wall 15 and a lower limiting wall 16, the latter having a sealed engagement with a rod-forming groove 22 situated at the periphery of the suction wheel 21. The upper wall 15 of the enclosure chamber is extended at its right end, as viewed in FIGS. 2 and 4, by a leaf spring 17 which covers a small part of the periphery of the suction wheel 21.

The upper wall 15 of the enclosure chamber includes several air inlet openings 18 which can be optionally opened or closed by way of the schematically illustrated valves 19. These are simply tiltable closure plates capable of being turned into engagement with the exterior surface of the upper wall 15 to close the openings 18, respectively, or capable of being turned to positions spaced from the upper wall 15 so as to uncover the openings 18, as shown, for example, at the left of FIG. 2.

The suction wheel 21 is supported for rotary movement on a hollow shaft 24 which serves as a suction conduit and which houses in its interior an adjustable butterfly valve 25. This suction conduit 24 communicates with the inlet 27 of a second fan 26. The hollow shaft 24 is closed at its end which is distant from the fan 26 and is formed at the region of the suction wheel 21 with an opening which communicates with a stationary air-guiding sector-shaped structure 29 which is located in the hollow interior of the suction wheel 21 and which forms with the sidewalls of the latter wheel a sector-shaped air passage 30 leading to the hollow interior of the shaft 24. The innermost portion 23 of the groove 22 at the periphery of the wheel 21 is perforated so that air will flow through the perforations into the sector 30 and from the latter into the suction conduit 24.

The fan 9 draws air which is extracted from the dust separating device 5 into the interior of the casing 7 through the inlet 10 and delivers the air under pressure out through the outlet 11 and into a dust separating device comprising a conical tube of louvered metal 31 situated within a perforated filter 32. This dust separating device 31 communicates with a pipe 33 which terminates in the interior on the inlet end of the convergent duct and accordingly this air stream induces a flow through the pneumatic supply means 3, 4, 5 of the tobacco which is introduced thereinto by the picker wheel. The fan outlet 28 communicates with a dust separating device 34 situated in the filter 32, and the outlet of the dust separating device 34 communicates through a pipe 35 with the inlet end of the convergent duct 3 of the pneumatic supply means. The dust which is extracted by the dust separating device 31, 34 is filtered by filter 32.

In order to separate excess tobacco at the periphery of the suction wheel 21, a pair of trimmers 36 are provided as indicated schematically at the lower right of FIG. 1.

The drive for the pin rollers and suction wheel 21 is derived from a single main driving motor 38.

The above structure operates as follows:

At the distributing structure which is shown at the upper left of FIG. I, the shredded tobacco which has not yet been separated into individual fibers to the desired extent is delivered in the form of a shower of tobacco by the picker wheel 2 into the inlet end of the convergent duct 3 of the pneumatic supply means. In the latter, as a result of the air flow from the fan 9, the tobacco in the form of a stream, is

directed to the outlet end 8 of the pneumatic supply means. As a result of the high speed movement of the stream of air, a continuously increasing acceleration of the shredded tobacco and a loosening of the fiber accumulations into individual fibers results. Additionally a radial preliminary compacting of the stream of tobacco in the frustoconical, tapered interior of the dust separating device 5 occurs.

The stream of air and tobacco 39 which issues from the outlet 8 has a cross section which is exceedingly small with respect to the cross section at the inlet end of the inlet end of the convergent duct 3. The stream is thus of a reduced crosssectional size and flows from the outlet opening 8 into the space 12, where the stream of tobacco is acted upon by the second suction stream, namely that derived through the perforations at the periphery of the suction wheel 21, this latter suction acting within the enclosure means 13-16. Thus, the stream of air and tobacco 39 in the chamber 12 is subjected to a second acceleration which provides the tobacco particles with a speed which is greater than that which they have in the dust separating device 5, so that there is an additional separa tion of the fibers. This second suction stream is of course derived by way of the fan 26 which acts through conduit 24 and the air-guiding elements 29 at the perforations in the innermost part of the groove 22 at the periphery of the wheel 24, and this latter additional suction can be controlled by adjustment of the valve 25.

The stream of air and tobacco 39 intersects the peripheral groove 22 of the wheel 21, which rotates at the speed with which the tobacco rod is formed, the tobacco being delivered from the stream 39 into a building plane of fiber deposition 40 at which the tobacco rod is initially formed, so that the tobacco rod starts at the building plane 40 where the fibers are deposited from the stream 39 which intersects the tobacco rod at this plane 40. The plane 40 is tangent to the innermost part of the groove at the periphery of the wheel 21, and forms an acute angle 0. Experience has shown that the position of the building plane 40, which extends transversely across the stream 39 and the tobacco rod, is of the utmost importance for the construction of the tobacco rod, and the optimum position of the plane 40 will depend upon the quality of the tobacco which is treated, with respect to the length or shortness of the fiber structure thereof. Within the chamber 12, therefore, the tobacco stream 39 is provided with the optimum direction.

As the tobacco particles move through the apparatus which treats the tobacco according to the method of the invention, the tobacco will initially have the speed V at the entrance into the inlet end of the convergent duct 3 at the region of the picker wheel 2, and the tobacco particles are accelerated through and beyond the speed V within the dust separating device 5 up to the speed V in the chamber 12, and this latter speed is on the order of l5+times the speed of movement V, of the tobacco rod at the periphery of the suction wheel 21. Thus, the stream of tobacco is delivered at the speed V to the building plane in the groove 22, and the tobacco fibers become layered to provide a uniformly dense and homogeneous structure for the tobacco rod, with the tobacco fibers automatically assuming primarily a position located at the angle a with respect to the axis of the tobacco rod, as is particularly apparent from FIGS. 3 and 5.

In order to be able to provide the best possible position for the building plane of fiber deposition 40, with respect to the length or shortness of the fibers of the shredded tobacco, it is possible to deflect the air and tobacco stream 39 from an upper limiting position downwardly so that the angle thereof which is determined by the direction of the stream 39 will change its position with respect to the center of the suction wheel 21. This adjustment is brought about by the selected positioning of the valves 19 at the upper wall of the enclosure means which encloses the stream 39 and which defines the chamber 12. As a result of the changed flow relationships resulting from deflection of the stream, the action of which can be intensified by an additional suction stream provided through suction outlets 20 as in FIG. 4, at the lower wall 16 communicating with any suitable source of suction, the

downwardly deflected stream 39 forms a building plane 40 which has a different angle a with the tangent to the periphery of the suction wheel at the place where the plane 40 intersects this periphery. The smaller the angle a, the greater the extent of intertwining of the fibers longitudinally of the cigarette rod, but at the same time the extent of transverse stressing of the tobacco fibers against the surrounding paper envelope of the cigarette becomes smaller. The structure and method of the invention therefore make it possible by a suitable selection of the direction of the stream 39 to provide an optimum relationship between both of these factors.

The tobacco rod which is thus formed in the groove 22 at the periphery of the suction wheel as a result of the suction action is held in the groove by suction and is delivered to a known structure which acts to complete the manufacture of the cigarettes. Thus, the rod of tobacco can be delivered to a further metering structure and can also be formed with an excess amount of material which can be cut away, for example by way of the separating structure which takes the form of the schematically illustrated separating discs 36. The air which is delivered under pressure from the fans 9 and 26 is freed of tobacco dust in the dust separating devices 31 and 34, in connection with the filter 32, and the relatively short particles of tobacco which are still held in the air stream are delivered by way of the pipes 33 and 35 back into the suction inlet 3.

We claim:

1. A device for manufacturing a continuous rod of pourable fibers such as fibers of shredded tobacco, comprising pneumatic supply means including convergent duct means open at one end, secondary duct means surrounding and communicating with the portion of said convergent duct means adjacent to the other end thereof, chamber means including inlet and discharge end portions, said inlet end portion communicating with said other end of said convergent duct means, suction wheel means including a grooved foraminous outer periphery defining a portion of said chamber means, means for projecting an air and tobacco stream through said convergent duct means to said other end thereof and into said chamber means, means for extracting a portion of the air from said air and tobacco stream and into said secondary duct means and means for extracting air from said air and tobacco stream through said foraminous groove into said suction wheel means whereby the air and tobacco stream will be compacted and formed into a filler stream which is removed from said chamber through said chamber means discharge end portion.

2. A device according to claim 1, wherein said portion of the convergent duct means adjacent to the other end thereof comprises a dust separating device including a conical tube of louvered metal.

3. A device according to claim 1 including adjusting means coacting with said chamber means for adjusting the direction of flow of the stream of particles from said pneumatic supply means to said groove located on the periphery of said suction wheel means.

4. A device according to claim 2 wherein said adjusting means includes inlet openings located along an upper wall portion of said chamber means for introducing ambient air through said openings into said chamber means.

5. A method for manufacturing a continuous rod of pourable fibers such as fibers of shredded tobacco in an apparatus including convergent duct means open at one end, secondary duct means surrounding and communicating with the portion of said convergent duct means adjacent to the other end thereof, chamber means including inlet and discharge end portions, said inlet end portion communicating with said other end of said convergent duct means, and suction wheel means including a grooved foraminous outer periphery defining.

6. A method according to claim 5 further comprising the step of adjusting the direction of flow of said stream through said chamber means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent O, 3 587 593 Dated June 28 1971 Friedrich Wilde et al. Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 69, cancel the period and insert a portion of said chamber means, comprising the steps of projecting an air and tobacco stream through said convergent duct means to said other end thereof where it will enter said chamber means, extracting a portion of the air from said air and tobacco stream into said secondary duct means, extracting air from the air and tobacco stream theough said formaminous groove into said suction wheel means whereby the air and tobacco stream will be compacted and formed into a filler stream thereby removing the filler stream from said chamber means..

Signed and sealed this 7th day of December 1971.

(SEAL) Attest:

, EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK -ttesting Officer Acting Commissioner of Patents FORM PC4050 (10-69) USCOMM.DC 0375 259 U 5 GOVERNMENT PRINTING OFFICE V359 O355334 

